Crack widening apparatus



April 1960 R. o. ASHBACK ETAL 2,931,634

CRACK WIDENING APPARATUS Filed Aug. 8. 1956 KR Y 60 E 4% m m nwm m w ma A. mWaw omk m AA an m 3% F @Q W. 9 3 RAW 2.

..n- LL United States Patent CRAK WIDENING APPARATUS Robert 0. Ashhack, Charles W. Weinke, Frank G. Kath, and Russell H. Swanson, all of St. Paul, Minn.

Application August 8, 1956, Serial No. 602,828

2 Claims. (Cl. 262-20) This invention relates to an improvement in pavement crack widening apparatus and deals particularly with a device useful in the repairing of concrete highways and the like.

Considerable difficulty is experienced in the repair of concrete highways which have been constructed with expansion joints which are too narrow to accomplish the desired results. Difficulty is also experienced in widening cracks which have developed in highways and which are too narrow to permit effective repair. Machines have been produced using a series of rotating cutters which cut into the concrete alongside of the crack and serve to widen the crack to the desired extent. Not only do these machines require two men to control and operate as well as an additional employee to clean out the widened cracks but also the construction is such that the cutting wheels wear out with extreme rapidity. In one instance, for example, the several cutting wheels of the unit required replacement after cleaning but sixty feet of the cracks to be widened. As the cutting wheels are expensive to purchase and as in some instances many miles of cracks have to be widened, the task has been extremely costly.

An object of the present invention lies in the provision of a crack widening apparatus which is portably mounted so that it may be handled by a single operator. This crack widening apparatus employs but a single cutting wheel. However, the cutting wheel is supported in such a way that it tends to adapt itself to the shape and form of the crack and to follow the crack more accurately than would otherwise be the case. As a result, the apparatus employing the single cutting wheel has widened the cracks more effectively and more quickly than the previous machines employed for this purpose and the single cutting wheel has been found to have a life which is about double the life of the plurality of cutting wheels on the previous devices designed for this purpose.

A feature of the present invention resides in the fact that the cutting wheel is mounted upon a generally horizontal shaft which is tiltably supported. In some instances it has been found that the cracks in the pavement formed through the use of relatively thin expansion joint material such as layers of tarred papers or the like are on a plane which is at an angle to the vertical. This is sometimes caused by the force of concrete being poured on one side of the expansion joint after the concrete has been poured on the opposite side thereof. By tiltingly supporting the cutter shaft and the motor driving the shaft, the cutter wheel may more accurately rout out the expansion joint forming material and widen the crack evenly on opposite sides thereof.

A further feature of the present invention resides in the fact that the cutter shaft is resiliently held from lateral movement or movement axially of the cutter shaft. Thus while the apparatus tends to hold the cutter wheel in a predetermined relation to the frame of the apparatus, the shaft and cutter supported thereby may shift laterally to some extent so as to better follow the shape and contour of the crack being routed.

A further feature of the present invention resides in the fact that the cutter wheel is resiliently held toward the pavement. In the past it has been felt necessary to hold the cutter wheel firmly against the concrete to widen the crack to a predetermined depth. We have found that by resiliently urging the cutter wheel toward the pavement, the cutter wheel can raise to some extent temporarily when it comes into engagement with a harder portion of the material being cut. At the same time, however, the cutter wheel is being urged through a proper depth so that in the operation of the cutter, it will only .normally raise temporarily and then will cut downwardly through the hardened portion of the pavement.

A further feature of the present invention lies in the simplicity of construction and the low cost at which the device may be constructed. Due to the fact that only a single cutting wheel is employed, the size of the power unit may be decreased and the entire construction may be greatly simplified. As a result, several machines may be purchased for the price of a single higher powered unit and as a result the same size crew can accomplish two or three times the work previously accomplished by the more expensive machines without any greater initial investment.

These and other objects and novel features of the present invention will be more clearly and fully set forth in the following specification and claims.

In the drawings forming a part of the specification:

Figure 1 is a perspective view of the apparatus in readiness for use.

Figure 2 is a perspective view of the frame of the apparatus shown in Figure 1.

Figure 3 is a sectional view through the cutter support, the position of the section being indicated by the line 33 of Figure 1.

Figure 4 is a sectional view through the cutter support mounting, the position of the section being indicated by the line 4-4 of Figure 3.

Figure 5 is a top plan view of the hinge connecting portions of the frame.

The general arrangement of the crack widening device A is best illustrated in Figure l of the drawings. This figure discloses a frame which is indicated in general by the numeral 16 and provided with laterally extending wheel supports 11 terminating in stub shafts such as 12 which rotatably support wheels 13. An internal combustion engine 14 or other source of power supply is mounted upon the frame 10 in a manner which will be later described. A handle unit 15 is provided by means of which the apparatus may be moved. A third wheel 16 is supported rearwardly of the frame 10 and a cutter support 17 is mounted upon the frame 10 to project forwardly therefrom. A cutter 19 is supported by the cutter frame 17 and is driven by the motor or engine 14 as will be later described.

The frame 10 is best illustrated in Figures 2, 3 and 4 of the drawings and includes a channel-shaped cross member 20 to which the wheel supports 11 are welded or otherwise secured to project laterally from the ends thereof. A bracket 21 is bolted or otherwise secured to the rear edge flange 22 of the channel 20 to support the third wheel 16. The bracket 21 includes a mounting plate 23 having apertures 24 near opposite ends thereof to accommodate bolts such as 25 to hold the bracket 21 to the channel member 20. Parallel rearwardly and downwardly inclined arms 26 are secured to the mounting plate 23 and are provided with aligned apertures 27 to accommodate the axle 29 of the wheel 16.

p A handle supporting lug 2Q is secured to the upper surface of the channel 20 at one end'thereof and a second Patented Apr. 5, 19560- ing is welded orotherwise secured to the flange 22 of the channel member near the other end thereof. The lugs 29 and 30 are provided with aligned pivot apertures 31 and 32 extending therethrough. These pivot apertures 31 and 32 are designed for a pivotal connection with the handle unit 15.

The handle unit 15 is not shown in great detail. However, in general, the handle unit includes a pair of parallel handle members 33 and 34 having rearwardly curved upper extremities 35 and 36, respectively. A cross member 37 connectes these handle members near the upper ends thereof and acts to hold them in parallel relation. The lower ends of the handle members 33 and 34 are flattened as indicated at 37 in Figure 5 of the drawings. Bolts 39 extend through the pivot apertures 31 and 32 and through the lower ends of the handle members 33 and 34 to pivotally support the handle.

A brace arm 49 extends rearwardly from the under surface of the channel member 2% and is welded or otherwise afiixed thereto intermediate the sides thereof. A lug 41 is welded to the rear end of the brace 40 and this lug 41 is apertured at 42. A rigid brace member 43 is attached at its upper extremity at 44 to the cross member 37 and is pivotally attached at its lower end to the lug 41. The member 43 is provided with a turn buckle 45 intermediate its ends so that the length of this member may be varied. The member 43 forms an adjustabie connection bet'een the brace 40 and the handle cross member 37 to hold the handles 35 and 36 at an adjusted elevation.

An angularly shaped engine mounting plate 46 is hingedly connected to one end of the channel 20 to overlie the surface of this channel. A tubular bearing 47 is welded or otherwise secured to the inner surface of the lug 29 and the engine mounting plate 46 is provided with aligned bearings 49 and 50 which are spaced apart a distance suflicient to admit the bearing 47 therebetween. bearings to pivotally connect the plate 46 to the channel 20 and so that the engine may be tilted about a horizontal axis extending longitudinally of the direction of travel of the apparatus.

A pair of forwardly and rearwardly extending bearing plates 52 and 53 are integral with the plate 46 and extend laterally therefrom. These plates are provided with parallel slots 54 and 55, respectively, through which bolts such as 58 may extend to connect the engine 14 to the engine mounting plate 46.

An arm 56 is secured to the under surface of the channel 2:) to project forwardly and rearwardly therefrom and a similar arm 57 is secured to the upper surface of the motor mounting plate 46 to extend parallel to the arm 56. Apertures 59 are provided in alignment through the projecting ends of the arms 56 and 57 and spacing bolts 60 may extend through the apertures and may be equipped with suitable locking nuts so as to hold the motor mounting plate 46 at a predetermined eleva tion at the end thereof opposite the hinged end. As the apertures 59 move out of alignment as the motor mounting plate 46 is swung upwardly, the holes are purposely made sufficiently large to permit the spacing bolts 69 to assume an angle of less than 90 from the arms through which they extend. As a result, the engine 14 and the parts connected thereto and driven thereby may be pivoted about the axis of thepivot 51.

The cutter support 17 includes an elongated channel member 61 having an opposed channel member 62 welded thereto in edge abutting relation at one end thereof to form a tubular body structure at one end of the support. As is. best indicated in Figures 3 and 4 of the drawings, a pivot lug 62a extends upwardly from the plate 46 near the hinged end thereof and near the forward edge of the frame. A pivot bolt 63 extends transversely through the lug 62a and also through slots 64 in the side flanges 65 and 66 of the upper channel mem- A pivot bolt 51 extends through the three ber 61. The slots 64 are preferably elongated longitudinally of the channel member to permit said cutter 17 with its cutter 19 to move longitudinally relative to both frames 10 and 46. Springs 67 and 69 are interposed between the lug 62 and the sides and 66 of the channel member 61, these springs encircling the pivot bolt 63.

With this arrangement, it will be clear that the cutter support 17 may pivot somewhat in a manner to cause the forward end of the cutter support to move in a lateral direction to one side of its normal position. The springs 67 and 69 tend to hold the cutter support centered but permit the cutter to move laterally an amount sufficient to follow the form of the crack being widened. The slots 64 also permit the support 17 to swing out of alignment with the direction of travel of the device to some extent.

A spring 70 is interposed between the plate 46 and the underface of the channel member 17 at a point spaced from the pivot 63. The spring 70 tends to urge the forward end of the cutter support downwardly but permits the forward end of this support to raise within limits by compressing the spring 70.

A cutter shaft 71 is pivotally supported by bearings 72 secured by bolts 73 or other suitable means to the undersurface of the channel member 62. The cutter 19 is supportedat one end of the shaft 71. Pulleys such as 74 are provided on the other end of the shaft 71, these pulleys being connected by belts 75 to suitable pulleys 76 on the drive shaft 77 of the engine 14. The pulleys 74 and 76 are properly proportioned to provide the desired cutter speed at which the cutter 19 will rotate.

The operation of the apparatus may now be described. If the crack to be widened comprises a narrow expansion joint between sections of a highway, the apparatus A is supported transversely of the highway with the cutter 19 substantially aligned with the crack to be widened. The engine 14 is started into operation and the apparatus is pushed by means of the handles 35 and 36, the cutter wheel 19 extending into the crack and widening it on either side of center. In view of the fact that the cutter may move to some extent in an axial direction due to the manner in which the cutter support 17 is mounted, the cutter wheel tends to follow the crack and to center itself so as to cut equally on opposite sides of center.

The cutter Wheels 19 are shown as comprising toothed blades, the teeth of which are formed of extremely hard and tough metal. During operation, the spring 76 tends to hold the cutter 19 at the proper depth in the crack. However, in the event the cutter wheel strikes an ex tremely hard portion of the pavement, the spring 70 may temporarily compress so as to prevent permanent injury to the cutter wheel. However, in normal operation, rotation of the cutter will soon force the cutter down to its proper depth cutting through the hardened portion of the pavement. Thus, as a result, the crack is widened to predetermined depth even though the cutter is free to rise to some extent due to compression of the spring 70.

In the event the crack is not in a vertical plane, the cutter may be inclined by pivoting the engine mounting plate 46 relative to the channel member 29. By properly adjusting the location of the engine mounting plate, the plane at which the cutter wheel will cut may be regulated.

It seems of utmost importance that the cutter be mounted somewhat in the manner described. While the specific arrangement of mounting may be varied, it seems important that the cutter wheel be resiliently urged into its normal cutting position and that the cutter be free to move laterally or in an axial direction to some extent so as to better conform with the shape of the groove being cut. By so arranging the cutter, much of the strain normally placed upon such cutters is avoided and the desired result is obtained in a simple and efiective manner.

In accordance with the patent statutes, we have described the principles of construction and operation of our crack widening apparatus, and while we have attempted to disclose the best embodiment thereof, it is desired to have it understood that obvious changes may be made within the scope of the following claims without departing from the spirit of the invention.

We claim:

1. A crack widening device including a main frame, wheels supporting said frame, an auxiliary frame pivotally supported on said main frame on an axis substantially longitudinally relative to the direction of movement of said Wheeled frame, an elongated cutter support having spaced parallel sides pivotally connected to said auxiliary frame and projecting forwardly therefrom, a cutter rotatably supported on a transverse axis to the forward end of said cutter support, means connecting said cutter support, and said auxiliary frame including a lug on said auxiliary frame intermediate the spaced sides of said cutter support and spaced therefrom, said spaced sides of said cutter support having opposed longitudinally extending slots therein, a pivot extending through'said lug and through said slots and compression springs encircling said pivot between each of said spaced sides and said lug, a power supply unit on said auxiliary frame, means connecting said power supply unit to said cutter to actuate the same, and means urging said cutter downwardly, whereby as said frame is moved, said cutter support may move laterally relative to said frame by compressing one of said springs and may move out of alignment with the path of movement of said frame by movement of said pivot in said slots.

2. A crack widening device including a wheeled frame, an elongated cutter support having spaced sides, means connecting said cutter support to said frame including a bearing on said frame intermediate said spaced sides of said cutter support, said spaced sides having opposed slots which are elongated longitudinally of said cutter support, a pivot extending through said slots and through said bearing, and a spring encircling said pivot and interposed between each of said spaced sides and said bearing, said pivot extending transversely with respect to the direction of travel of said frame and said cutter support extending forwardly from said frame, a power unit on said frame, a cutter rotatably supported at the forward end of said cutter support on an axis substantially parallel to said pivot axis, and means connecting said power unit to said cutter to rotate the cutter, whereby when said cutter is engaged in a crack, said cutter support may shift axially of said pivot by compressing one of said springs, and may swing out of parallel relation to the direction of travel of said frame by movement of said pivot longitudinally of said slots.

References Cited in the file of this patent UNITED STATES PATENTS 

